hmmm... we used to it so much. was that a surprisingly new knowledge for you? in the (cold) wintertime, birds feel lack of fats in their diet, so fatty sunflower seeds are an excellent solution, and besides, some birds really love to get this fat directly from lard! tits and woodpeckers, of those whom I know, are very big fans of lard! its a pure fun to take pictures of tits foraging the lard hanging off the branches in the park.